121.
A compound $$'A'$$ when treated with \[HN{{O}_{3}}\] ( in presence of \[{{H}_{2}}S{{O}_{4}}\] ) gives compound $$'B',$$ which is then reduced with $$Sn$$ and $$HCl$$ to aniline ? The compound $$'A'$$ is
\[A\xrightarrow{HN{{O}_{3}}/{{H}_{2}}S{{O}_{4}}}B\xrightarrow{Sn/HCl}{{C}_{6}}{{H}_{5}}N{{H}_{2}}\]
This indicates that $$B$$ is \[{{C}_{6}}{{H}_{5}}N{{O}_{2}}\] and hence $$A$$ is \[{{C}_{6}}{{H}_{6}}\]
122.
The source of nitrogen in Gabriel synthesis of amines is
A
sodium azide, $$Na{N_3}$$
B
sodium nitrite, $$NaN{O_2}$$
C
potassium cyanide, $$KCN$$
D
potassium phthalimide, $${C_6}{H_4}{\left( {CO} \right)_2}{N^ - }{K^ + }$$
Both aliphatic and aromatic primary amines react with chloroform and alc. $$KOH$$ to give isocyanides or carbylamines and the reaction is known as carbylamine reaction.
$${C_6}{H_5}N{H_2} + CHC{l_3} + \mathop {3KOH}\limits_{{\text{(alc}}{\text{.)}}} \to $$ \[\underset{\begin{smallmatrix}
\text{Phenyl} \\
\text{isocyanide}
\end{smallmatrix}}{\mathop{{{C}_{6}}{{H}_{5}}NC}}\,+3KCl+3{{H}_{2}}O\]
125.
The compound which on reaction with aqueous nitrous acid at low temperature produces an oily nitrosamine is
NOTE : Secondary amines ( aliphatic as well as aromatic ) react with nitrous acid to form N - nitrosoamines.
$${\left( {{C_2}{H_5}} \right)_2}NH + HONO \to $$ $$\mathop {{{\left( {{C_2}{H_5}} \right)}_2}N - N = O + {H_2}O}\limits_{{\text{N - Nitrosodiethylamine}}} $$
Both aliphatic and aromatic secondary amines reacts with $$NaN{O_2} + HCl$$ or $$\left( {HN{O_2}} \right)$$ to form $$N$$ - nitrosamines which are insoluble in dilute mineral acids and separate out as neutral yellow oily compounds.
127.
In the following reactions, the product $$S$$ is \[\xrightarrow[\text{ii}.\,Zn,\,{{H}_{2}}O]{\text{i}.\,{{O}_{3}}}R\xrightarrow{N{{H}_{3}}}S\]
No explanation is given for this question. Let's discuss the answer together.
129.
Identify the correct pathway to convert propanoic acid to ethylamine. The reagent represented by $$A, B$$ and $$C$$ are \[C{{H}_{3}}C{{H}_{2}}COOH\xrightarrow{A}X\xrightarrow{B}\] \[Y\xrightarrow{C}C{{H}_{3}}C{{H}_{2}}N{{H}_{2}}\]
Guanidine is most basic because its conjugate acid is stabilized by two equivalent resonance structures,.
Further $${2^ \circ }$$ amines are more basic than $${1^ \circ },$$ while amides are least basic due to delocalisation of the lone pair of electrons on $$N$$
Thus the correct order of basicities is